Make-Up/Break-Out Device For Drilling Hammers

ABSTRACT

A make-up/break-out device for use with a hammer used in horizontal directional drilling operations. The hammer comprises a drill bit assembly and a housing that are connected via low helix angle threads. The make-up/break-out device is used with the hammer to tighten or loosen the connection between the drill bit assembly and the housing. The make-up/break-out device comprises a vise arm, a lever arm, and drive arm. The drive arm reacts torque on both the vise arm and the lever arm which in turn react torque on the drill bit assembly and the housing

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of provisional patent application Ser. No. 61/725,320, filed on Nov. 12, 2012, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to horizontal directional drilling machines. Specifically, the present invention relates to a make-up/break-out device for use with threaded hammer assemblies.

BACKGROUND OF THE INVENTION

Hammers used in horizontal directional drilling operations are well known in the art. They are typically used for fracturing rock or penetrating tough soil and may be pneumatic or fluid driven. The hammers work by repeatedly striking the face of a drill bit assembly connected to a housing against the face of a borehole. During linear boring operations, the hammer is usually turned only in one direction; thereby, constantly tightening the threads used to connect the drill bit assembly to the housing. Due to this, the drill bit assembly and the housing are typically connected via high helix angle threads or multi-start threads. These types of threads require less torque to unthread the connection.

More recent hammers have been adapted to steer underground during horizontal directional drilling operations. These hammers are configured with a steering feature that allows the hammer to deviate from a linear borepath upon direction of an operator. The steering feature may comprise an asymmetrical drill bit and/or a deflection in the axis of the hammer relative the rotational axis of the bit to produce offset forces that cause the hammer to deviate from a linear path, Steering may be achieved by rotating the drill bit assembly in the reverse direction over a limited angle of rotation. However, rotating the drill bit assembly in the reverse direction may cause the drill bit assembly to loosen from the housing when the drill bit assembly and the housing are connected via high helix angle threads.

SUMMARY OF THE INVENTION

The present invention is directed to an apparatus to make-up or break-out a drill bit assembly and a housing used m horizontal directional drilling operations. The drill bit assembly comprises external low helix angle threads and at least two pockets on opposing sides of an outer surface. The housing comprises internal low helix angle threads formed to correspond to the external low helix angle threads. The apparatus comprises a vise arm, a lever arm, and a drive arm. The vise arm comprises a gripper to hold the housing against rotation. The lever arm comprises an opening and at least two pins disposed within the opening to engage the pockets to secure the drill bit assembly within, the opening. The drive arm is connected to the vise arm and the lever arm. Operation of the drive arm drives movement of the lever arm to rotate the external low helix angle threads of the drill bit assembly relative to the internal low helix angle threads of the housing.

The present invention is also directed to an apparatus to make-up or break-out a drill bit assembly and a housing of a hammer used in horizontal directional drilling operations. The drill bit assembly comprises external low helix angle threads and at least two pockets on opposing sides of an outer surface. The housing comprises internal low helix angle threads. The apparatus comprises a vise arm, a lever arm, and a drive arm. The vise arm comprises a gripper to hold the housing against rotation. The lever arm comprises an opening fanned by two arms extending from the lever arm, and at least one pin disposed within each of the two arms to engage the pockets to secure the drill bit assembly within the opening. The drive arm is connected to the vise arm and the lever arm. Operation of the drive arm drives movement of the lever arm to rotate the external low helix angle threads of the drill bit assembly of the hammer relative to the internal low helix angle threads of the housing of the hammer.

The present invention is further directed to a method for disassembling a hammer used in underground drilling operations. The method comprises the steps of securing a vise arm to a housing comprising internal low helix angle threads, engaging an opening of a lever arm with a drill bit assembly comprising external low helix angle threads, and inserting at least two pins into the opening of the lever arm and into at least two pockets formed on the drill bit assembly to secure the drill bit assembly to the lever arm. The method further comprises the step of extending a drive arm connected to both the vise arm and the lever arm to rotate the drill bit assembly of the hammer relative to the housing of the hammer to loosen the external low helix angle threads of the drill bit assembly from the internal low helix angle threads of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a drill bit assembly and a housing of a hammer.

FIG. 2 is a modified isometric view of the hammer showing a make-up/break-out device affixed to the drill bit assembly and the housing.

FIG. 3 is a front view of the device without the hammer disposed within the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the figures and first to FIG. 1, shown therein is a drill bit assembly 10 and a housing 12 of a hammer 14. The hammer 14 is formed by connecting the drill bit assembly 10 to the housing 12 via external low helix angle threads 16. The drill bit assembly 10 comprises the external low helix angle threads 16, and the housing 12 comprises corresponding internal low helix angle threads 18. In order to maintain the threaded connection between the drill bit assembly 10 and the housing 12 during steering operations, the present invention utilizes fine threads with low helix angles. The low helix angle threads 16 and 18 have an angle in the range of 0.25 to 4.0 degrees. Low helix angle threads allow for a much tighter connection between the drill bit assembly 10 and the housing 12 and require a higher breakaway torque to unthread the connection, as compared to high helix angle threads. The higher breakaway torque maintains a tight connection between the drill bit assembly 10 and the housing 12 when rotating in the reverse direction. The higher breakaway torque created from using low helix angle threads also decreases the likelihood of the drill bit assembly 10 coming loose from the housing 12 during drilling operations than if high helix angle threads were used. However, it is difficult when in the field to easily tighten the connection between the drill bit assembly 10 and the housing 12, as well as produce enough torque to unthread the connection.

Continuing with FIG. 1, the drill bit assembly 10 comprises a drill bit 22 and a chuck 24. The chuck 24 comprises a shank 26 and the external low helix angle threads 16. The shank 26 of the chuck 24 also comprises a plurality of pockets 28, to be described later on. The drill bit 22 and the chuck 24 are held together by retainer rings 30. The drill bit 22 may comprise a steering feature 32 and a plurality of raised carbide buttons 34. The steering feature 32 is the asymmetrical structure of the drill bit 22 face. The housing 12 shown in FIG. 1 also comprises a threaded end 20. The threaded end 20 is adapted to connect to a series of drill pipes (not shown) that connect to a drilling machine at the ground surface (not shown).

Turning now to FIG. 2, a make-up/break-out device 36 for use with the hammer 14 is shown. The drill bit assembly 10 and the housing 12 of the hammer 14 are shown disposed within the device 36. The device 36 may be used to assemble or tighten the connection between the drill bit assembly 10 and the housing 12, or the device may be used to disassemble or loosen the drill bit assembly from the housing. The device 36 comprises a vise arm 38, a lever arm 40, and a drive arm 42. The vise arm 38 comprises a first end 44 and a second end 46. The first end 44 of the vise arm 38 comprises a gripper 48. The gripper 48 engages with the housing 12 to hold the housing against rotation. The gripper 48 shown in the figures comprises a chain; however, one of skill in the art will recognize that the gripper may comprise a jaw mechanism or other device suitable to hold the housing against rotation.

Continuing with FIG. 2, the lever arm 40 comprises a first end 50 and a second end 52, The first end 50 of the lever arm 40 comprises an opening 54 (FIG. 3) formed by two arms 56 extending out from the lever arm. The opening 54 of the lever arm 40 forms an arc shape and engages with the chuck 24 of the drill bit assembly 10. A set of pins 60 are shown disposed within each of the two arms 56 of the lever arm 40. The pins 60 extend through apertures 62 within each of the two arms 56 and engage with at least two of the plurality of pockets 28 (FIG. 1) of the drill bit assembly 10. The pins 60 may be threaded through the apertures 62 to a desired distance or until they securely engage with the pockets 28. When the pins 60 are securely engaged with the pockets 28, they hold the drill bit assembly 10 against rotation relative to the lever arm 40.

The drive arm 42 shown in FIG. 2 is connected to the second end 46 of the vise arm 38 and to the second end 52 of the lever arm 40. The drive arm 42 connects to the second end 46 of the vise arm 38 via a pin 66, and the drive arm connects to the second end 52 of the lever arm 40 via a pin 68. The pins 66 and 68 are held in place by retainer pins 70. The drive arm 42 drives movement of the lever arm 40 and the vise arm 38. The drive arm 42 shown in the figures comprises a hydraulic cylinder 72, which comprises a piston 74 and a cylinder 76. When the piston 74 extends from the cylinder 76, the drive arm 42 lengthens and causes the lever arm 40 and the vise arm 38 to rotate in opposite directions. Similarly, when the piston 74 retracts within the cylinder 76, the drive arm 42 shortens and causes the lever arm 40 and vise arm 38 to rotate in opposite directions. One of skill in the art will recognize that the drive arm 42 may comprise any mechanism capable of driving rotational movement of the vise arm 38 and the lever arm 40.

In operation, the lever arm 40 and the drill bit assembly 10 rotate together when the drive arm is actuated. This occurs because the lever arm 40 tightly grips the drill bit assembly 10 when the pins 60 are engaged within the pockets 28, which allows the force applied to the lever arm by the drive arm 42 to be transferred to the drill bit assembly. Prolonged use of the drill bit assembly 10 in abrasive conditions may cause wear and tear on the pockets 28. Since the pins 60 can be threaded to varying depths needed to secure the pins to the pockets 28, force may be transferred from the lever arm 40 to the drill bit assembly 10 when abrasion has reduced the depth of the pockets.

Continuing with FIG. 2, the vise arm 38 and the housing 12 rotate together when the vise arm rotates. This occurs because the gripper 48 tightly grips the housing 12, which allows the force applied to the vise arm 38 by the drive arm 42 to be transferred to the housing 12. The gripper 48 is adapted to wrap around the housing 12 and apply tension to an outer circumference of the housing. The gripper 48 also comprises gripping pads 78 which comprise sharp features 80 (FIG. 3) that are adapted to bite into an outer surface of the housing 12. Torque applied to the vise arm 38 is transferred to the housing 12 via the gripper 48 and the gripping pads 78.

Turning to FIG. 3, the make-up/break-out device 36 is shown in more detail. The drive arm 42 is shown pivotally connected to the second end 46 of the vise arm 38 via the pin 66. The drive arm 42 is also shown pivotally connected to the second end 52 of the lever arm 40 via the pin 68. The retainer pins 70 are shown holding the pins 66 and 68 in place. The gripper 48 shown in the FIG. 3 comprises a chain. A screw 82 and a bolt 84 are shown attached to the gripper 48. The bolt 84 pulls the chain to tighten the gripper 48 on the housing 12 prior to operating the device 36. The sharp features 80 of the gripping pads 78 used to bite into the outer surface of the housing 12 are also shown in greater detail. The pin 60 is also shown extending through the arm 56 and into the opening 54 of the first end 50 of the lever arm 40.

Prior to horizontal directional drilling operations, the hammer 14 is configured by connecting the drill bit assembly 10 to the housing 12. This is accomplished by threading the external low helix angle threads 16 on the drill bit assembly 10 to the internal low helix angle threads 18 on the housing 12. The make-up/break-out device 36 is then employed to tighten the connection between the drill bit assembly 10 and the housing 12. To tighten the connection, the device 36 is attached to the hammer 14 by engaging the gripper 48 with the housing 12 and engaging the lever arm 40 with the chuck 24 of the drill bit assembly 10. The gripper 48 secures the housing 12 by tightening the bolt 84 on the screw 82 to tighten the chain. The chuck 24 of the drill bit assembly 10 is secured to the lever arm 40 by placing the opening 54 of the lever arm on the shank 26 of the chuck. The pins 60 are then threaded through the apertures 62 of the two arms 56 until the pins are positioned within the pockets 28 formed in the shank 26 of the chuck 24.

The device 36 tightens the connection between the drill bit assembly 10 and the housing 12 via operation of the drive arm 42. The drive arm 42 draws the vise arm 38 and lever arm 40 either closer together or farther apart depending on which direction works to tighten the connection. If the drive arm 42 comprises the hydraulic cylinder 72, the piston 74 will either extend or retract from the cylinder 76 to move the vise arm 38 and the lever arm 40 closer or farther apart. The motion of the drive arm 42 reacts torque on both the vise arm 38 and the lever arm 40 which in turn react torque on the housing 12 and the drill bit assembly 10, causing them to rotate in opposite directions and tighten the threaded connection between them. Once a tight connection is formed between the housing 12 and the drill bit assembly 10, the hammer 14 may be used in horizontal drilling operations. The strong break away torque imposed on the hammer 14 by the low helix angle threads 16 and 18, helps to maintain the connection between the drill bit assembly 10 and the housing 12 when the drill bit 22 rotates in the reverse direction.

In order to disassemble the drill bit assembly 10 from the housing 12 the device 36 is again engaged with the hammer 14. The drive arm 42 then moves the vise arm 38 and the lever arm 40 in the opposite direction the arms were moved to tighten the connection. The torque from the drive arm 42 is applied to the vise arm 38 and the lever arm 40 and then to the housing 12 and the drill bit assembly 10. The housing 12 and the drill bit assembly 10 are then turned in opposite directions until the threaded connection is loosened and the drill bit assembly may be disassembled from the housing.

Various modifications can be made in the design and operation of the present invention without departing from its spirit. Thus, while the principal preferred construction and modes of operation of the invention have been explained in what is now considered to represent its best embodiments, it should be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described. 

What is claimed is:
 1. An apparatus to make-up or break-out a drill bit assembly and, a housing used in horizontal directional drilling operations, the drill bit assembly comprising external low helix angle threads and at least two pockets on opposing sides of an outer surface, and the housing comprising internal low helix angle threads, the apparatus comprising: a vise arm comprising a gripper to hold the housing against rotation; a lever arm comprising an opening and at least two pins disposed within the opening to engage the pockets to secure the drill hit assembly within the opening; and a drive arm connected to the vise arm and the lever arm; wherein operation of the drive arm drives movement of the lever arm to rotate the external low helix angle threads of the drill bit assembly relative to the internal low helix angle threads of the housing.
 2. The apparatus of claim 1 wherein the opening of the lever arm is an arc shape which comprises two apertures formed in the lever arm for receiving the pins.
 3. The apparatus of claim 2 wherein the two apertures are threaded.
 4. The apparatus of claim 3 wherein the pins are threaded into the two apertures.
 5. The apparatus of claim 1 wherein the drive arm comprises a hydraulic cylinder.
 6. The apparatus of claim 1 wherein the drill bit assembly comprises a chuck and a drill bit.
 7. The apparatus of claim 6 wherein the chuck comprises the at least two pockets.
 8. The apparatus of claim 1 wherein the drill bit assembly comprises a plurality of pockets formed in a circle around an outer circumference of the drill bit assembly.
 9. The apparatus of claim 1 wherein the drill bit assembly is adapted to rotate in two different directions.
 10. The apparatus of claim 1 wherein the drill bit assembly comprises a steering feature adapted to deviate the housing from a linear path.
 11. The apparatus of claim 1 wherein the drill bit assembly comprises retaining rings.
 12. The apparatus of claim 1 wherein the gripper comprises a chain.
 13. The apparatus of claim 1 wherein the angle of the external low helix angle threads and the internal low helix angle threads is in the range of 0.25 to 4.0 degrees.
 14. An apparatus to make-up or break-out a drill bit assembly and a housing of a hammer used in horizontal directional drilling operations, the drill bit assembly comprising external low helix angle threads and at least two pockets on opposing sides of an outer surface, and the housing comprising internal low helix angle threads, the apparatus comprising: a vise arm comprising a gripper to hold the housing against rotation; a lever arm comprising an opening formed by two arms extending from the lever arm, and at least one pin disposed within each of the two arms to engage the pockets to secure the drill bit assembly within the opening; and a drive arm connected to the vise arm and the lever arm; wherein operation of the drive arm drives movement of the lever arm to rotate the external low helix angle threads of the drill bit assembly of the hammer relative to the internal low helix angle threads of the housing of the hammer.
 15. The apparatus of claim 14 wherein each of the two arms comprises an aperture for receiving each pin.
 16. The apparatus of claim 15 wherein the apertures are threaded.
 17. The apparatus of claim 16 wherein each pin is threaded into each aperture.
 18. The apparatus of claim 14 wherein the drive arm comprises a hydraulic cylinder.
 19. The apparatus of claim 14 wherein the drill bit assembly comprises a chuck and a drill bit.
 20. The apparatus of claim 19 wherein the chuck comprises the at least two pockets.
 21. The apparatus of claim 14 wherein the drill bit assembly of the hammer comprises a plurality of pockets formed in a circle around an outer circumference of the drill bit assembly.
 22. The apparatus of claim 14 wherein the drill bit assembly of the hammer is adapted to rotate in two different directions.
 23. The apparatus of claim 14 wherein the drill bit assembly of the hammer comprises a steering feature adapted to deviate the housing from a linear path.
 24. The apparatus of claim 14 wherein the drill bit assembly comprises retaining rings.
 25. The apparatus of claim 14 wherein the gripper comprises a chain.
 26. The apparatus of claim 14 wherein the angle of the external low helix angle threads and the internal low helix angle threads is in the range of 0.25 to 4.0 degrees.
 27. The apparatus of claim 14 wherein the drill hit assembly comprises an asymmetrical steerable drill bit.
 28. A method for disassembling a hammer used in underground drilling operations, the method comprising the steps of: securing a vise arm to a housing comprising internal low helix angle threads; engaging an opening of a lever arm with a drill bit assembly comprising external low helix angle threads; inserting at least two pins into the opening of the lever arm and into at least two pockets formed on the drill bit assembly to secure the drill bit assembly to the lever arm; and extending a drive arm connected to both the vise arm and the lever arm to rotate the drill bit assembly of the hammer relative to the housing of the hammer to loosen the external low helix angle threads of the drill bit assembly from the internal law helix angle threads of the housing.
 29. The method of claim 28 further comprising threading the pins through the lever arm and into the pockets to a distance needed to secure the drill bit assembly within the opening of the lever arm.
 30. The method of claim 28 wherein extending the drive arm comprises operating a hydraulic cylinder.
 31. The method of claim 28 further comprising providing a chuck of the drill bit assembly with the at least two pockets. 